PRODUCT SUMMARY
SKY74076: Receiver for Dual-Band CDMA and GPS Mobile
Handset Applications
Applications
•
CDMA and GPS phones
stage cellular LNA (high, mid, and bypass) and a high gain GPS
LNA.
After RF LNA signal amplification and filtering from the antenna,
the received signal is mixed down from RF to IF. There are
separate mixers for CDMA cellular and GPS modes. The CDMA
mixer has balanced outputs for the IF SAW filters and can be
combined externally to mate to a single-ended SAW filter. The
GPS mixers have a differential output for an external LC bandpass
filter. After IF filtering, the IF signal is amplified by a Variable Gain
Amplifier (VGA) and sent to an I/Q demodulator, resulting in
baseband I/Q signals at the output.
The SKY74076 is also designed with two Local Oscillator (LO)
input ports, one for the CDMA mixer and one for the GPS mixer.
These mixers operate at different RF frequency inputs, but have
the same IF frequency output. This usually refers to a single IF
(SIF) plan at 183.6 MHz.
The CELL_LO signal (pin 30) provides an LO port for the CDMA
cellular mixer. In the cellular band, an internal divider divides the
frequency by two, which provides the LO input to the cellular
mixer. Only one external VCO is required for the UHF PLL.
Additionally, the mixer LO signal is coupled and amplified
internally, which provides another RF signal to drive the
transmitter upconverter LO port.
The VGA has a minimum dynamic range of 90 dB with a control
voltage range of 0.5 to 2.5 V, which is common to all modes. A
VHF oscillator operates with external tank circuits to provide LO
frequencies for the I/Q demodulator in the cellular, PCS, and GPS
modes.
The noise figure, gain, and 3
rd
order Input Intercept Point (IIP3) of
each stage in the receiver chip are optimized to meet the system
requirements for CDMA modes according to TIA/EIA-98-C. The
SKY74076 design employs BiCMOS technology for low cost, high
performance, and a high level of integration.
A block diagram of the SKY74076 is shown in Figure 1.
Features
•
Three-step gain control cellular LNA
•
GPS LNA
•
External resistor to adjust LNA bias current
•
Independent CDMA and GPS mixers
•
Buffer LO signal for transmit upconverter
•
Dynamic range VGA, 90 dB
•
VHF oscillator, 200 MHz to 600 MHz
•
Battery cell operation (2.7 V < Vcc < 3.3 V)
•
RFLGA™ (40-pin, 6 x 6 x 1 mm) Pb-free (MSL3, 260
°C
per
JEDEC J-STD-020) package with downset paddle
Skyworks offers lead (Pb)-free “environmentally
friendly” packaging that is RoHS compliant
(European Parliament for the Restriction of
Hazardous Substances).
Description
The SKY74076 is a single Intermediate Frequency (IF), dual-band,
receiver for Code Division Multiple Access (CDMA) and Global
Positioning System (GPS) applications.
The device is a highly integrated super-heterodyne receiver.
Except for the Surface Acoustic Wave (SAW) filters and matching
components, the SKY74076 incorporates all the components
required to implement the receiver chain, from the Low-Noise
Amplifier (LNA) to the In-Phase and Quadrature (I/Q) demodulator
stages. Two LNAs are in the front-end receiver: a three-step gain
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
103087C • Skyworks Proprietary and Confidential information • Products and Product Information are Subject to Change Without Notice • January 24, 2005
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SKYWORKS [ SKYWORKS SOLUTIONS INC. ]
